The invention relates to a method and a device for folding sheet-like copies, for example folding copies, which are produced in folders arranged downline from web-processing rotary printing machines.
Heretofore disclosed in the prior art, by way of the published European Patent Document EP 0 663 363 B1, is an arrangement for guiding web-like materials with at least one roller core and a plurality of lamella rings positioned thereon, and also a process for producing the arrangement. For guiding web-like materials, for example paper, textile or sheet-material webs, the arrangement is provided with at least one roller core and a plurality of lamella rings which are positioned thereon and formed of an elastic material. The lamella rings are arranged symmetrically to the axial central plane of the roller core and are lined up, in a mirror-inverted manner, in rows extending outwardly from the center. Axially abutting one another, they form a virtually continuous surface. The lamella rings have at least one predetermined point of inflection, the cross section of the lamella rings being somewhat Z-shaped.
When subjected to radial pressure, for example initiated by stressing which is exerted via an outgoing material web, the outer circumference is displaced axially and symmetrically to the axial center plane. In this regard, the cylindrical surface maintains the parallelism thereof to the roller axis. In this construction known heretofore from the prior art, the lamella rings may preferably be produced from (natural) rubber, plastics or similar materials.
The published German Non-prosecuted Patent Application (DE-OS) 29 05 545 is concerned with a folding roller. Coverings formed of pliant or yieldable plastic material are inserted in the jacket of the folding roller. Roller-surface regions formed of metallic material are left free between the coverings, the inserted coverings projecting slightly beyond the metallic-material regions. The coverings are prefabricated rings formed of slightly elastically deformable, for example elastomeric, plastic material. The rings can be inserted under prestressing in annular grooves which are provided in the roller jacket, the rings having, over the entire width thereof, a grooved arrangement formed by grooves extending at least approximately parallel to the folding-roller axis. The metallic surface regions between the rings, in contrast, have a smooth groove-free surface. This construction is intended to provide a folding roller which executes a particularly reliable conveying operation, allows air to flow out without obstruction, can be produced relatively straightforwardly and inexpensively, has a relatively long service life and has regions subjected predominantly to wear, which are renewable, as such, relatively easily.
Moreover, the published German Patent Document DE 37 43 642 A1 has disclosed a further folding roller. This folding roller has a cylindrical core element whereon, in order to form recesses at predetermined positions, sleeve-like sections formed of elastomeric material, and sleeve-like sections formed of metal are arranged so that they are displaceable relative to one another. In order to ensure that the metal sleeve-sections, which are knurled on the outside, are secured against relative rotation, circumferential grooves are recessed in the inner surface of the sections, and O-rings formed of elastomeric material are inserted in the circumferential grooves. Axial displacement of the metal sleeve-like sections is possible due to the O-rings, yet a friction lock in the circumferential direction is assured at all times. With this construction, it is possible, in an extremely straightforward manner, to adjust the recess between the individual sections in accordance with respectively provided linear applications of glue.
With multilayered folding copies, such as folded products having, for example, 8, 16, 24, 32, 48 or 64 pages, the folds of the innermost copy layers may rupture. Upon opening a multilayered folding copy which is held together at the folding spine thereof by connecting elements, for example, staples, it is possible, with fold rupturing, for the innermost layer to drop out of the copy, for example, a periodical or a magazine, because it is no longer held in place; the staples cannot any longer exert a retaining force on the innermost copy layer, which is also referred to as the central layer. At the folding spine thereof, the central layer undergoes a deflection of approximately 180xc2x0, due to which the respective printing substrate is subjected to very high stressing. Due to the printing, the subsequent drying, and the remoistening and cooling of the web, the printing substrate of the material web is exposed to widely varying thermal influences, as a result of which the mechanical properties thereof can change very unfavorably. In particular, the mechanical stability of the web may be reduced considerably by embrittlement, with the result that pronounced stressing, for example, in the form of a 180xc2x0-deflection, promotes the occurrence of fold ruptures. The rest of the layers which enclose the central layer are relatively unsusceptible to the occurrence of fold ruptures because the folding spine in each copy layer becomes rounded to an appreciable extent as the number of copies increases.
Departing from the aforementioned technical problem and the outlined prior-art solutions therefor, it is an object of the invention to provide a method and device for folding sheetlike copies, which avoids the occurrence of fold ruptures on folding copies and increases the copy quality to a significant extent.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a method for folding sheet-like copies, respectively, made up of a plurality of copy layers, whereby open ends and closed folding spines are formed on the copies by folding operations, which comprises forming the folding spine on the inner copy layers of the copy in a manner that the folding spine is interrupted by non-folded sections.
In accordance with another mode, the method of the invention includes maintaining the folding spine rounded in the region of the non-folded sections.
In accordance with a further mode, the method of the invention includes locating the non-folded sections of the folding spine in a region of stapling or stitching positions.
In accordance with an added mode, the method of the invention includes arranging the stapling or stitching positions on the folding spine in a format-dependent manner.
In accordance with an additional mode, the method of the invention includes forming the folding spine parallel to the grain of material forming the copy.
In accordance with yet another mode, the method of the invention includes forming the folding spine with non-folded sections by pushing the copy layers into a nip between folding rollers.
In accordance with yet a further mode, the method of the invention includes forming the folding spine with non-folded sections, during a cross-folding operation, upon transfer of the copies from one copy-guiding cylinder to a next following copy-guiding cylinder.
In accordance with another aspect of the invention, there is provided a device for folding sheet-like copies, respectively, made up of a plurality of copy layers, the copies being formed by folding operations with regions having open ends and closed folding-spine regions, and folding components for producing the folding-spine regions on the copies, at least one of the folding components being provided for acting linearly on the copy layers of a multilayered folding copy, comprising surfaces defining recesses provided in the folding components for forming a folding spine on the copy layers of the respective copies, the folding spine including non-folded sections and longitudinally folded sections.
In accordance with a further feature of the invention, the recesses are formed on the folding components with a width corresponding to a measurement of the non-folded sections.
In accordance with an added feature of the invention, the recesses have a depth in the folding components which produces spaces, in the region of the folding spine, for surrounding connecting elements.
In accordance with an additional feature of the invention, the recesses are arranged on the folding components in a format-dependent manner.
In accordance with yet another feature of the invention, for stapling or stitching positions for a first folding format, the recesses are arranged at a given spacing A on an untrimmed length of the copy layers.
In accordance with yet a further feature of the invention, a recess, for a stapling or stitching position for a second folding format, is arranged at a given spacing B approximately in the center of an untrimmed length of the copy layer.
In accordance with yet an added feature of the invention, the recess is provided as a revolving annular groove formed in folding rollers defining a folding nip.
In accordance with yet an additional feature of the invention, the recesses are formed as pockets in jacket surfaces of the folding components formed as folding rollers.
In accordance with still another feature of the invention, the pockets are formed on the circumference of the folding rollers so that the pockets extend over a circular-arc sector of the respective jacket surface.
In accordance with still a further feature of the invention, the recesses are arranged on a folding blade in a region of a folding edge of a second longitudinal folding arrangement.
In accordance with an additional aspect of the invention, there is provided a folding copy formed of a plurality of copy layers with open ends and closed regions on a folding spine, the folding spine comprising inner copy layers including non-folded regions with a rounded formation and longitudinally folded regions.
In accordance with a concomitant aspect of the invention, there is provided a folder for folding sheet-like copies, respectively, made up of a plurality of copy layers, the copies being formed by folding operations with regions having open ends and closed folding-spine regions, and folding components for producing the folding-spine regions on the copies, at least one of the folding components being provided for acting linearly on the copy layers of a multilayered folding copy, comprising surfaces defining recesses provided in the folding components for forming a folding spine on the copy layers of the respective copies, the folding spine including non-folded sections and longitudinally folded sections.
The advantages which can be achieved by the method and device. according to the invention are diverse in nature. The arrangement of non-folded zones, which is distributed over the length of the folding spine, avoids excessive weakening of the printing substrate. The material regions which remain non-folded in the region of the folding spines of the innermost copy layers of a multilayered copy give the innermost copy layers a higher mechanical strength, with the result that excessive weakening of respective layers is avoided in the region of the folding spines of the innermost layer, parallel to the grain direction. This provides, in the folding spine of the copy material, material bridges which, by virtue of the avoidance of any weakening, in particular in the region of the connecting zones of the copy layers, provide a reliable hold for the connecting element, for example, staples or stitching.
In an advantageous refinement of the method proposed according to the invention, the non-folded sections of the innermost copy layers remain rounded and thus provide sufficient space for closing the connecting elements of the copy layers, for example, staples or stitching. The non-folded regions of the folding spine are preferably placed in the positions in which, at a later stage, the staples or stitching are introduced into the copy in order to hold the individual copy layers together. The stapling or stitching position and thus the position of the non-folded regions of the folding spine are preferably placed in format-dependent positions, for example in the head and foot regions of an A4-copy or in the border regions of a delta-fold copy.
In order to minimize the mechanical stressing to which the printing substrate is subjected, the folding spines which are to be produced are preferably located parallel to the grain direction in the printing substrate.
According to another mode of the method, a folding spine may be formed with these interrupting non-folded sections by the copy layers or the copies being pushed into a nip between folding rollers. This allows the folding-spine formation proposed according to the invention to be used in the production of a second longitudinal fold in the folder; a further mode of the method is for the folding spine, interrupted by non-folded sections, to be formed, during the cross-folding operation, upon transfer of the copy layers from the circumference of one copy-guiding cylinder onto the next copy-guiding cylinder, for example the jaw cylinder in the case of cross folding.
The device proposed according to the invention is intended for folding sheet-like copies which include a plurality of copy layers, and comprises folding components which, for their part, are provided with recesses or cutouts forming the respective folding spine on the individual copy layers of a multilayered copy, the folding spine, for its part, being interrupted by non-folded sections. In an advantageous configuration, the recesses are formed on the folding components in a width which corresponds to the longitudinal dimension of a non-folded section on the folding spine of the copy layers. In addition to such longitudinal dimensions of the non-folded regions, it is possible for the depth of the recesses in the folding components to produce, in the region of the folding spine, a space which encloses the connecting elements, such as staples or stitching, for example.
The individual recesses are preferably arranged on the folding components in a format-dependent manner, in particular, recesses for stapling or stitching positions for a first folding format being arranged at a spacing A on the untrimmed length of the copy layers, and also recesses for stapling positions for a second folding format are arranged at a spacing B approximately in the center of the untrimmed length of the copy layers. The recesses on the folding components may be formed as continuously encircling or revolving annular grooves in mutually cooperating folding rollers which, for their part, define a folding nip. Another embodiment results from forming the recesses as pockets in the respective jacket surfaces of the folding rollers, the pocket length in the circumferential direction being such that a circular-arc sector of the jacket surface of the respective folding roller defines the pocket length. Finally, it is possible to arrange the recesses on a folding blade of a second longitudinal folding arrangement, the recesses, which are likewise recessed again in a format-dependent manner, being formed in the edge region of the folding blade by which the latter acts upon the copy layers, which are to be folded linearly, as they are pushed between the folding rollers.
By the method and device proposed according to the invention, it is possible to produce folding copies comprising a plurality of copy layers, the ends of which are open and which have a closed folding-spine region, the folding spine of inner copies containing non-folded regions with a rounded formation.
The solution proposed according to the invention for forming a fold on sheet-like copies, whether this is a cross fold, longitudinal fold, delta fold, a double parallel fold or the like, may advantageously be used in folders which may be arranged downline of web-processing or sheet-processing rotary printing machines. The folder may be equipped with sets of pins, but the folder may also be one which operates without pins. In addition to a possible use downline of sheet-processing rotary printing machines, the solution according to the invention can be used particularly advantageously in web-processing printing machines, for example, for newspaper or web job printing.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and device for folding sheet-like copies, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.